Project 3

1. Calculate the Nominal Velocity Ratio (V_R):

V_R = n_p/average n_g

2. Specify a reasonable Module (m):

m = 4                                                                                (mm)

3. Select the number of teeth on the pinion (N_p):

Hint:

Minimum number of teeth to avoid interference for pinions having 20° pressure angles is 18

Select N_p= 28

4. Calculate the Pinion Diameter (d_p):

d_p = N_p ´ m                                                                         (mm)

5. Calculate the number of teeth on the gear (N_g):

N_g = N_p ´ V_R

Round-off the calculated value to a closest higher integer value

6. Calculate the Gear Diameter (d_g):

d_g = N_g ´ m                                                                         (mm)

7. Calculate & Check the final Output Speed (n_g):

n_g = n_p ´ (N_p/N_g)                                                                  (rpm)

Check if this value falls within the specified output speed range, i.e. (270~280 rpm)

8. Calculate the Center Distance (C):

C = (N_p+N_g)m/2                                                                   (mm)

9. Calculate the Pitch Line Velocity (n _t):

n _t = p d_pn_p/60000                                                                (m/sec.)

10. Calculate the Tangential Force (W_t):

W_t = P ´ 1000/n _t                                                                (N)

11. Calculate the Face Width (F) of the gears:

F = (8~16)m                                                                         (mm)

12. Calculate Bending Stress on the pinion (s _tp) and gear (s _tg):

                                                (MPa)

13. Calculate the Contact Stress (s _c) on the gear pair:

                                          (MPa)

 

14. Select Materials for the pinion and gear depending upon the hardness values for each stress

Stress	Brinell Hardness	Selection Procedure
Bending Stress on Pinion	x	} }
Contact Stress on Gear Pair	y
Bending Stress on Gear	z